We are proud to present the papers from the 17th Refinement Workshop, co-located with FM 2015 held in Oslo, Norway on June 22nd, 2015.

Refinement is one of the cornerstones of a formal approach to software engineering: the process of developing a more detailed design or implementation from an abstract specification through a sequence of mathematically-based steps that maintain correctness with respect to the original specification.

This 17th workshop continued a 20+ year tradition in refinement workshops run
under the auspices of the British Computer Society (BCS) FACS special interest
group. After the first seven editions had been held in the UK, in 1998 it was
combined with the Australasian Refinement Workshop to form the International
Refinement Workshop, hosted at The Australian National University. Eight more
editions have followed in a variety of locations, all with electronic
published proceedings and associated journal special issues, see the workshop
homepage at www.refinenet.org.uk for more details.

Like previous editions, the 17th edition was co-located with a major formal
methods conference, this year we were delighted to be co-located with the FM international conference, which again proved to be a very productive pairing
of events. The workshop had 10 presentations, and of those we have selected 9
papers for presentation in the published proceedings following a peer review
process. The papers cover a wide range of topics in the theory and application
of refinement.

This is the third volume that has appeared as an EPTCS proceedings, and we would like to thank the editorial board (and in particular Rob van Glabbeek) for their help and cooperation in making this happen. As last time, this edition had a small Program Committee, whose names appear below, and we thank them for their work.

The organisers would like to thank everyone: the authors, BCS-FACS, EPTCS, and the organisers of FM 2015 for their help in organising this workshop, the participants of the workshop, and the reviewers involved in selecting the papers.